Gripper-tensioning mechanism for presses



Oct. 16, 1928.

F. S. ENGLISH ET AL GRIPPER TENSIONING MECHANISM FOR PRBSSEQ Original Filed May 6, 192-5 2 Sheets-Sheet 1 #2 5 g E Oct.'16; 192s. 1,687,753

F. S. ENGLISH El AL GRIPPER TENSIQNING MECHANISM FOR PRESSES 2 Sheets-Shet 2 Griginal Filed m 6, 1925 Patented @et. 16, 1928.

UNITED S TATEST PATENT OFFICE"; g

FRED- S. ENGLISH AN D THOMAS L. PERRY, OF NEW LONDON CONNECTICUT, ASSIGNORS TO THE BABCOCK PRINTING mass or CONNECTICUT.

vmnurao'runrne COMPANY, A CORPORATION enrrrnn-rnlvsromne MECHANISM FOR rnnssns.

Original application filed May 6, 1925, Serial No. 28,355. Divided and this; application filed Septemberfl,

The present case is a division of our co-- pression cylinder of the press and on the shaft are mounted a series of curved fingers, commonly called grippers, whlch impinge against the forward edge of the sheet which. is to be printed or cutand creased, pressing the edge of the sheet against the forward or leading edge of the impression portion of the cylinder. Generally the grippers are closed on the sheet by spring action, and they are opened '7 by means of a cam through a lever action which turns the gripper shaft. When the grippers first act on the sheet the latter is stationaryand the inertia of the sheet must be overcome practically instantly. This places a heavy burden upon, the grippers when the sheet is first started, and requires much greater, holding force than is afterwards necessary to carry the sheet around with the impression cylinder. If there is any slippage between the sheet and grippers while the sheet is starting fromthedead stop position, this will affect the register of the printing. The object o-fthe present inven tion is to provide means for'placing an additicnal pressure or tension upon the grippers while the inertia of the sheet is being overcome, and this pressure maybe continued during any portion of the revolution of the cylinder, although in practice it has been found necessary to apply this additionalpressure only during the starting o f'the sheet a nd'foir a very short period thereafter. If the ordi vnary springs usually employed for closing the grippers upon the sheet are made sul'lici ntly stiff to provide the extra pressure required during thestarting of-the sheet, there is diflicultyin opening the grippers to de liver or take the sheet and the gripper operating mechanism in such caseis subject to rapid wear. In thepresent case we have shown means separate from the ordinary means for pressingthe grippers, which places an additional or auxiliary pressure upon them at the moment they are closed upon the ingpress.

being printed or cut and 'eration with the flatform on the bed or type cylinder, these latter parts not being represented in the drawings. a

Serial No. 133214.

tion has been applied,

press to which our invenv Figure 2 is a plan view of the same, and I Figure 3 is an enlarged sectional view of the principal part of the invention.

In the drawings we have shown the impression cylinder 1 such as isemployed in a two-revolution printing press, and it is to be understood that this may represent the impression cylinder of a cutting and creaspression surface of the cylinder .while it is creased in coopor circular form At 2 we have shown the end ofthe feed table which is arranged adjacent the surface of the The sheet engages around the imimpressioncylinder 1' and 1 from'whic hthe sheets are fed over the forward edge of this board into position to be taken by the grippers on'the impression cylinder. Itv may be here stated that the mechanism here described may be used in connection with any other cylinder onwhich the sheet travels and At 4 we have shownthe shaft which extends longitudinally of the cylinder and it is mounted on a suitable bracket i of thecylinder and it is known as the gripper shaftand it carriesa number of grippers 5 of which only one is shown in the drawing. These grippers are secured to the shaft in such position that the tips of thegrippers will impinge the sheet against the leading edge of the impression portion of the cylinder. The ordinary device for operating these grippersfto grip and release the sheet comprises a crank arm and cam, as shown in our said copending apthe principle of operation will be the same. i

36 and the vlatter is secured to alever 37 V which is fixed to the shaft 38 mounted in the cylinder to oscillate in the bearings 39 and 40. Outside of the cylinder there is a lever arm 54s secured to the shaft 38 and it Carries a roller 40 which is adapted to be acted upon by a cam 41 stationarily' hired to a portion 42 of the press frame. This roller 40 is held pressed against the, cam by means of spring 13 which surrounds the rod n. One end of the spring presses against the lever 37 while the other presses against a spring step 46 attached to the cylinder at 47. The pawl 35 is forced against the shoulder 48 by means of a compression spring l9 which surrounds the rod 50 and is compressed between the spring step 51 which is part of the lever 37, and against the under side of the pawl 35. There are nuts 52 and 53 at opposite ends of the rod 50 and by adjusting these nuts the pawl 35 may be regulated in position to engage the shoulder 48.

In the drawings we have shown this device in the position in which the pawl is engaged with the shoulder 480f thedisc 34 at which time the spring 49 is exerting pressure upon the pawl 35 and through the disc 34lcausing a rotating pressure upon the shaft 4 to apply auxiliary foroeto the grippers 5 to hold them pressed against the edge of the sheet at the time the latter is being taken and until the inertia of the sheet has beenovercome. Considering the cylinder 1 turned back from the position shown in the drawings until the roller 40 is engaged with the high portion of the cam 4L1, at this time the grippers 5 will be slightly open to allow the forwardedge of the sheet to be fed to the forward edge of the impression portion of the cylinder. At this time the lever 37 will be rocked slightly anticlockwise in Figure 1 so that the point of the pawl 35 will be disengaged from the shoulder 48 of the disc 34; and it will be slightly below the shoulder 4L8. As the cylinder proceeds to move to the left from the position above described, the roller L0 will finally run into the lower portion of the cam ll and the point of'the pawl will move slightly clockwise and also upwardly in relation to the disc 34 so that it will come into contact with the shoulder 4-8 just before or at the instant the grippers are pressed against the sheet by the ordinary gripper closing mechanism,. which latter will be the same as in said copending application. Any slight irregularity of adjustment of the parts may be compensated for through the spring .19. In case the cylinder is turned backwardly the spring e9 will allow the grippers to be opened without injury.

As the cylinder continues to revolve anticlockwise in Figure 1 and after the roller 40 has moved to the lowest point on the cam 4.1 the roller 4-0 will be gradiuilly lifted by reason of the fact that the cam ll has slightly increasing radius following its lowest point;

and this causes the pawl 35 to be released so that additional auxiliary pressure on the V shaft sis released at or before the time approaches for the opening of the grippers. In a two-revolution press the cylinder is in raised position at the time the grippers take the sheet and it is lowered at theitime the grippers are opened to deliver the sheet, and this raising and lowering motion of the cylinder in relation to the fixed cam 4C1 in itself is sufficient to throw the auxiliary mechanism out of action at the time the grippers are opened, if desired. v

Itis obvious that the still or inactive period of the cam can be of any convenient length so that the additional pressure on the grippers may be applied merely for a brief time when the sheet is taken and thenimmediately released, or the additional pressure may be maintained during a considerable portion of the printing cycle of the press. The mainrequirement is that the additional pressure is to be exerted at the time the sheet is first taken by the grippers and until the inertia of the sheet has been overcome.

I-Iaving described our invention, whatwe claim is:

-- 1. In a press the combination of a cylinder adapted to carry a sheet, grippers thereon for engaging and holding the sheet to move with the cylinder, said grippers being mounted on a shaft having means adapted to be ent gaged by a latch, a latcharranged to operate thereon to press the grippers upon the sheet, and means for automatically causing said latch to act on said grippers to press the sheet while in the initial gripping position and for automatically releasing said latch before the opening of said grippers. V

' 2. In a press the combination of a cylinder adapted to carry a sheet, grippers thereonfor engaging and holding the sheet to move with said cylinder, said grippers beingmounted on a shaft having means adapted to be engaged by a latch, a latch arranged to operate thereon to press thegri'ppers uponthe sheet, and means for automatically causing said latch to act on said grippers t0 pressthe sheet while in the initial gripping position and for automatically releasing said latch before the opening of said grippers, embodying a cam for releasing said latchv p 3. In a press the combination of a cylinder adapted to carry a sheet, grippers thereon for engaging and holding the sheet to move with said cylinder and adapted to be actuated by the ordinary closing means, said grippers being mounted on a sh'aft,'means operating independently of the ordinary gripper actuating means for pressing the grippers on the sheet and including means on .said shaft adapted to be engaged by a latch, a latch arranged to operate thereon to press the grippers upon the sheet, and a stationary cam for releasing said latch.

' 4. In a press the combinationof a cylinder adapted to carry a sheet, grippers thereon for holding and moving the sheetand adapted to be actuated by the ordinary closing means and means for operating independently of the ordinary actuating means for pressing the grippers on the sheet, said grippers being mounted on a shaft having means adapted to be engaged by a latch,'a latch carried by said cylinder and spring means for operating the same to press the grippers, and means for causing said latch to engage said means on said shaft when the sheet is taken by the grippers and for releasing thelatch prior to the opening of the grippers.

5. In a press the combination of a cylinder adapted to carrying a sheet, grippers-therecylinder and having an 'arm, a cam for oper- 'ating on said lever arm to rock said lever, a

spring for holding said lever armengaged with said cam, a latch carried by said lever for engaging the means on said shaft, and

spring acting on saidlatch to exert'a clospressure on the grippers.

igned at the city and county of New London, State of Connecticut,

August, 1926. V

FRED S; ENGLISH;

THOMAS L. PERRY. i

this 18th day of 

